additive index

https://doi.org/10.1351/goldbook.14424
Quantification of the joint action of toxicants in mixture by adding measures of their toxicity calculated in relation to the toxicity of a reference toxicant.
Source:
PAC, 2009, 81, 829. (Glossary of terms used in ecotoxicology (IUPAC Recommendations 2009)) on page 835 [Terms] [Paper]